(Bloomberg) -- Former U.S. National Security Advisor John Bolton told news service Axios that President Donald Trump’s administration should admit its approach to end North Korea’s nuclear arms program has “failed.”

Bolton suggested the Trump administration is bluffing about stopping North Korea’s nuclear ambitions and it would be “very unusual” for his former employer to say that they got it wrong, he said in an exclusive interview released on Monday.

Bolton said the U.S. could be doing more to tighten sanctions choking North Korea’s economy, which would force the hand of leader Kim Jong Un. “The idea that we are somehow exerting maximum pressure on North Korea is just unfortunately not true,” he told Axios.

The former White House official, who sat with the U.S. president across the table from Kim at summits in Singapore and Hanoi, doubted the administration “really means it” when Trump and top officials pledged to stop North Korea from having deliverable nuclear weapons — “or it would be pursuing a different course,” Axios reported him as saying.

Trump ousted the hawkish Bolton in September after seemingly cutting him out of the decision-making process on many major issues. Bolton has long been one of the biggest skeptics of Pyongyang, becoming so reviled that North Korea’s state-run media regularly singled him out for criticism and called him a “nasty troublemaker.”

Bolton’s comments come just days before the year-end deadline Kim has given Trump to bring a new offer to the table or risk Pyongyang taking a new path that could rattle regional security.

“We’ve tried. The policy’s failed. We’re going to go back now and make it clear that in a variety of steps, together with our allies, when we say it’s unacceptable, we’re going to demonstrate we will not accept it,” he said.

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Bolton also mocked Deputy Secretary of State Stephen Biegun for saying North Korea’s missile launches and belligerent statements were not helping bring peace on the Korean Peninsula, calling the comments a “clear winner in the Understatement of the Year Award contest.”

As nuclear talks have sputtered, North Korea has been building its weapons arsenal, Bolton told Axios.

“We’re now nearly three years into the administration with no visible progress toward getting North Korea to make the strategic decision to stop pursuing deliverable nuclear weapons,” Bolton said.

To contact the reporter on this story: Jihye Lee in Seoul at jlee2352@bloomberg.net

To contact the editors responsible for this story: Niluksi Koswanage at nkoswanage@bloomberg.net, Jon Herskovitz, Muneeza Naqvi

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